Attempts to isolate and characterize a proposed triacyglycerol synthetase specifier factor will continue. In addition, its mechanism of action will be probed indirectly by examining the time-course of incorporation of palmitate into various metabolic intermediates of the triacyglycerol synthetic pathway. Experiments on the proportion of endogenous and exogenous substrates incorporated into triacyglycerols by microsomal preparations of adipose tissue will be initiated. In these experiments, per-deuterated palmitate an per-deuterated sn-3-phosphoglycerol will be employed as substrates; and the triacylglycerols will be examined by mass spectrometer. Purification and characterization of the soluble enzyme system from Butyrivibrio fibrisolvens that hydrogenates cis-9, trans-11 octadecadienoate will be carried out. Studies on the structure and mechanism of action of the endogenous electron donor in B. fibrisolvens will be continued. BIBLIOGRAPHIC REFERENCES: Hunter, William James, Baker, Frederick C., Rosenfeld, Ira S., Keyser, Jody B., and Tove, Samuel B. "Biohyrogenation of Unsaturated Fatty Acids. Hydrogenation by Cell-Free Preparations of Butyrivibrio fibrisolvens." J. BIOL. CHEM. 251(8): 2241-2247. (1976). Banis, Robert J., Roberts, Cynthia S., Stokes, Gilbert B., and Tove, Samuel B. "Procedure fo Enzymatic Synthesis and Isolation of Radioactive Long Chain Acyl-CoA Esters." ANAL. BIOCHEM. 73:1-8. (1976).